Fix user generation with email_prefix to support multiple users

[socksprox]

Problem

When using the user generation endpoint with both email_prefix and generate_count parameters, only one user was being created instead of the specified count.

For example, this request would only generate 1 user instead of 5:

{
  "email_prefix": "company",
  "email_suffix": "example.com", 
  "password": "password123",
  "expired_at": 1757973600,
  "plan_id": 5,
  "generate_count": 5,
  "download_csv": false
}

Solution

• Modified the generate() method to properly handle both email_prefix and generate_count parameters
• Added new multiGenerateWithPrefix() method for bulk user creation with prefixed emails
• Users are now created with incremented email addresses: prefix_1@domain.com, prefix_2@domain.com, etc.
• Maintains full backward compatibility for single user generation
• Includes proper email validation and database transaction handling

Changes Made

1. Modified generate() method: Added logic to call multiGenerateWithPrefix() when both email_prefix and generate_count are provided
2. Added multiGenerateWithPrefix() method: New method that generates multiple users with incremented email prefixes
3. Email validation: Checks that none of the generated email addresses already exist before creating any users
4. Transaction safety: Uses database transactions for safe batch creation
5. Feature parity: Supports both JSON response and CSV download functionality

Testing

The fix has been tested with the original failing request and now properly generates 5 users with emails:

• company_1@example.com
• company_2@example.com
• company_3@example.com
• company_4@example.com
• company_5@example.com

Backward Compatibility

✅ Single user generation (no generate_count) continues to work as before
✅ Multiple user generation without email_prefix (random emails) continues to work as before
✅ All existing functionality is preserved

[socksprox]

@cedar2025 Please check it out, I tested this commit on my developing xboard instance and it worked well